Grant: 17-009R
Project Title: Incubation temperature effects on sea turtle hatchling fitness
Project Manager: Dr. Sarah Milton
Organization: Florida Atlantic University (Research and Educational Institute)
Grant Amount: $14,931.00
Completion Date: 2018-12-10
Summary: Increasing global temperatures will impact sea turtle populations in a variety of ways, from the likelihood of feminization of populations to direct mortality and more subtle, far ranging effects on behavior and fitness. Hatchling mortality due to thermal stress may vary with species (due e.g. to difference in nest depth or peak laying season), and/or may vary with stage of development: less or more developed embryos may be differentially sensitive, especially as embryonic metabolism can increase nest temperatures above ambient by several degrees. Reported effects of incubation temperature also include changes to self-righting, crawl speeds, and swimming. Most experimental results though come from artificial constant temperature incubation experiments and may not be directly applicable to natural nests where incubation temperature does not remain constant. Studies in other reptiles also suggest incubation conditions affect hormones and development, with long term effects on growth and behavior, yet such effects have not been examined in sea turtles at all. In this study, we will examine metrics of hatchling fitness in loggerhead sea turtles incubated under controlled laboratory conditions, as well as record thermal profiles in green and loggerhead nests in situ on the Boca Raton beach. Upon emergence, hatchlings will be tested for righting response, and crawl and swim speeds. Plasma corticosterone and blood heat shock proteins will be determined as measures of thermal stress that may impact frenzy capacity. Plasma measures will be repeated in post-hatchling turtles retained for the Wyneken study. Hatchlings from in situ nests will be similarly tested, with swim speeds and rates of predation determined in the field as real measures of fitness that may reflect incubation temperatures. Unhatched eggs will also be collected and staged to determine if there are correlations between periods of thermal stress and embryonic mortality.
Results: